Selected ATcT [1, 2] enthalpy of formation based on version 1.140 of the Thermochemical Network [3]

This version of ATcT results[3] was generated by additional expansion of version 1.130 to fully include the highest-level electronic structure computations described in reference [4].

Dihydrogen

Formula: H2 (aq, undissoc)
CAS RN: 1333-74-0
ATcT ID: 1333-74-0*1000
SMILES: [H][H]
InChI: InChI=1S/H2/h1H
InChIKey: UFHFLCQGNIYNRP-UHFFFAOYSA-N
Hills Formula: H2

2D Image:

[H][H]
Aliases: H2; Dihydrogen; Hydrogen molecule; Hydrogen; Molecular hydrogen; Diatomic hydrogen; o-Hydrogen; p-Hydrogen
Relative Molecular Mass: 2.01588 ± 0.00014

   ΔfH°(0 K)   ΔfH°(298.15 K)UncertaintyUnits
-4.099± 0.080kJ/mol

Top contributors to the provenance of ΔfH° of H2 (aq, undissoc)

The 1 contributors listed below account for 97.2% of the provenance of ΔfH° of H2 (aq, undissoc).

Please note: The list is limited to 20 most important contributors or, if less, a number sufficient to account for 90% of the provenance. The Reference acts as a further link to the relevant references and notes for the measurement. The Measured Quantity is normaly given in the original units; in cases where we have reinterpreted the original measurement, the listed value may differ from that given by the authors. The quoted uncertainty is the a priori uncertainty used as input when constructing the initial Thermochemical Network, and corresponds either to the value proposed by the original authors or to our estimate; if an additional multiplier is given in parentheses immediately after the prior uncertainty, it corresponds to the factor by which the prior uncertainty needed to be multiplied during the ATcT analysis in order to make that particular measurement consistent with the prevailing knowledge contained in the Thermochemical Network.

Contribution
(%)		TN
ID		 Reaction Measured Quantity Reference
97.279.1 H2 (g) → H2 (aq, undissoc) ΔrG°(298.15 K) = 17.761 ± 0.05 kJ/molYoung 1981


Most Influential reactions involving H2 (aq, undissoc)

Please note: The list, which is based on a hat (projection) matrix analysis, is limited to no more than 20 largest influences.

Influence
Coefficient		 TN
ID		 Reaction Measured Quantity Reference
0.97279.1 H2 (g) → H2 (aq, undissoc) ΔrG°(298.15 K) = 17.761 ± 0.05 kJ/molYoung 1981
0.02779.2 H2 (g) → H2 (aq, undissoc) ΔrH°(298.15 K) = -4.098 ± 0.30 kJ/molYoung 1981
0.00079.3 H2 (g) → H2 (aq, undissoc) ΔrG°(298.15 K) = 17.6 ± 4.00 kJ/molNBS Tables 1989
0.00079.4 H2 (g) → H2 (aq, undissoc) ΔrH°(298.15 K) = -4.2 ± 4.00 kJ/molNBS Tables 1989

References
1   B. Ruscic, R. E. Pinzon, M. L. Morton, G. von Laszewski, S. Bittner, S. G. Nijsure, K. A. Amin, M. Minkoff, and A. F. Wagner,
Introduction to Active Thermochemical Tables: Several "Key" Enthalpies of Formation Revisited.
J. Phys. Chem. A 108, 9979-9997 (2004) [DOI: 10.1021/jp047912y]
2   B. Ruscic, R. E. Pinzon, G. von Laszewski, D. Kodeboyina, A. Burcat, D. Leahy, D. Montoya, and A. F. Wagner,
Active Thermochemical Tables: Thermochemistry for the 21st Century.
J. Phys. Conf. Ser. 16, 561-570 (2005) [DOI: 10.1088/1742-6596/16/1/078]
3   B. Ruscic and D. H. Bross,
Active Thermochemical Tables (ATcT) values based on ver. 1.140 of the Thermochemical Network (2024); available at ATcT.anl.gov
4   J. H. Thorpe, J. L. Kilburn, D. Feller, P. B. Changala, D. H. Bross, B. Ruscic, and J. F. Stanton,
Elaborated Thermochemical Treatment of HF, CO, N2, and H2O: Insight into HEAT and Its Extensions
J. Chem. Phys. 155, 184109 (2021) [DOI: 10.1063/5.0069322]
5   B. Ruscic,
Uncertainty Quantification in Thermochemistry, Benchmarking Electronic Structure Computations, and Active Thermochemical Tables.
Int. J. Quantum Chem. 114, 1097-1101 (2014) [DOI: 10.1002/qua.24605]
6   B. Ruscic and D. H. Bross,
Thermochemistry
Computer Aided Chem. Eng. 45, 3-114 (2019) [DOI: 10.1016/B978-0-444-64087-1.00001-2]
Formula The aggregate state is given in parentheses following the formula, such as: g - gas-phase, cr - crystal, l - liquid, etc.
Uncertainties The listed uncertainties correspond to estimated 95% confidence limits, as customary in thermochemistry (see, for example, Ruscic [5] and Ruscic and Bross[6]).
Note that an uncertainty of ± 0.000 kJ/mol indicates that the estimated uncertainty is < ± 0.0005 kJ/mol.
Website Functionality Credits The reorganization of the website was developed and implemented by David H. Bross (ANL).
The find function is based on the complete Species Dictionary entries for the appropriate version of the ATcT TN.
The molecule images are rendered by Indigo-depict.
The XYZ renderings are based on Jmol: an open-source Java viewer for chemical structures in 3D. http://www.jmol.org/.
Acknowledgement This work was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences and Biosciences under Contract No. DE-AC02-06CH11357.